Hi Aspenoracle,
Thanks for hopping in the forum. While you can edit the plugin’s code to change the width. It might be better to add the css directly to your theme’s style.css file. Then the changes will stay when the plugin is updated.
To edit your style.css file, go to the WordPress admin area and click on Appearance > Editor. Then select your theme in the upper right, scroll down the page and look for the style.css file.
You can scroll to the bottom of the text on the left and add the css at the end of the code to adjust the rollover color and change the input width.
This css will change the color to red when rolling over, you can change it to what ever you want.
#mc_signup_submit:hover {
background-color: red;
}
This css will change the width to 40% instead of the 100% that it is the default.
.mc_merge_var input{
width: 40%;
}
Let us know if you have any other questions.
-mc_d